The present invention relates generally to a method and a device for discharging material from a silo. More specifically, the present invention relates to a stuffing box for a silo having a reciprocating frame.
Silos are large receptacles used to store and discharge materials. Silos usually have an inlet at the top and an outlet at the bottom. Virtually any type of material may be placed into a silo and later discharged. Viscous wet materials, however, are difficult to discharge because they are not free-flowing. For example, municipal waste sludge stored in silos tends to clump together and form bridges over a discharge opening. Discharge devices may be incorporated into the bottom of a silo above a discharge opening to dislodge material bridges and induce sludge flow.
Several types of discharge devices for coaxing sludge out of silos are known. In rectangular and square silos, the push floor design is common. The push floor consists of a series of hydraulically driven ladders that move linearly to convey sludge toward a discharge opening. In circular or polygonal silos, rotating scrapers or movable frames may be incorporated near the silo floor. In the case of rotating scrapers, radial arms extending from a central body include rotating or oscillating scrapers that break up clumps of sludge. In the case of movable frames, an open frame structure reciprocates back and forth over the silo floor pushing and pulling sludge along with it and over a discharge opening. While inclusion of a discharge device near the floor of a silo is known, the construction and operation of such discharge devices are far from ideal.